1. Field of the Invention
The present invention relates to a method for adjusting a head module, a method for manufacturing an inkjet head, and an inkjet head, and in particular, to a method for adjusting a head module, a method for manufacturing an inkjet head, and an inkjet head in view of the landing interference of ejected droplets.
2. Description of the Related Art
In the field of inkjet image formation, in order to realize high imaging resolution and high productivity, a head module in which multiple nozzles are arranged in a two-dimensional manner is formed, and a plurality of head modules are arranged in a width direction of a recording medium, thereby constituting an elongated head (full line-type head) which covers an image formation region of the overall width of the recording medium. The inkjet imaging system (single pass system) is known, in which the recording medium is relatively scanned in a direction perpendicular to a width direction of the elongated head only once to form an image on the recording medium.
When a plurality of head modules are arranged to form an inkjet head as described above, if the head modules are not linked with each other precisely, overall head modules are moved (shifted) in a direction of either one of adjacent head modules, causing a problem that nozzle intervals differ in the link portion of the head modules, and quality of an image to be formed is degraded. If the head modules can be arranged with high precision, it is possible to maintain favorable image quality in the link portion. However, it is technically difficult to arrange the head modules with high precision, and cost (apparatus cost and the number of operations) is required for the arrangement with high precision.
In order to arrange the head modules with high precision, for example, JP2011-56880A describes that, in a line printer in which a plurality of heads are arranged, a test pattern is created and the amount of adjustment of a nozzle position of a head is calculated from the test pattern to adjust the position of the head. JP2009-23292A describes that, in a line head in which a plurality of heads are arranged, an image for position adjustment is printed and the nozzle position is determined and confirmed visually to move the head. JP2006-341518A describes that the relative position of a nozzle is set by the amount of deflection of ink, thereby forming a high-quality image.